Square and Cube Roots Quiz Set 009

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Question 1

How many 4 digit numbers are their whose squares end in 2?

 A

0.

 B

2.

 C

3.

 D

4.

Soln.
Ans: a

It is not possible for the square of any number to end in 2, 3, 7 or 8. Hence the answer is 0.


Question 2

What is the least number that should be subtracted from 0.0509 to make it a perfect square?

 A

0.05.

 B

0.06.

 C

0.02.

 D

0.03.

Soln.
Ans: a

We know that 0.03 = $√0.0009$, so by inspection we can see that 0.0509 - 0.05 will give us 0.0009.


Question 3

What is the value of $√{(11 - 2√3) × (11 + 2√3)}$?

 A

$√109$.

 B

9.

 C

10.

 D

√3.

Soln.
Ans: a

By inspection, we can easily see that the formula (a - b) × (a + b) can be used to simplify like this: $√{(11)^2 - (2√3)^2}$, which is same as $√{121 - (2^2 × 3)}$, which is same as $√{121 - 12}$ = $√109$.


Question 4

If $√2$ = 1.41, then what is the value of ${√2}/5$ − $4/{√2}$?

 A

-2.546.

 B

-2.665.

 C

-2.412.

 D

-2.049.

Soln.
Ans: a

The given expression can be simplified to ${{(√2)^2} - 5 × 4}/{5 × √2}$, which is same as ${2 - 20}/{5 × √2}$, which is same as ${-18/{5 × √2}$. Rationalizing, we get ${-18/{5 × √2} × {√2/√2}$ which gives ${-18√2}/10$ which = -2.546.


Question 5

What is cube root of 0.000729?

 A

0.09.

 B

0.729.

 C

0.81.

 D

0.081.

Soln.
Ans: a

We can see that 0.09 × 0.09 × 0.09 = 0.000729, so cube root is 0.09.


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Creative Commons License
This Blog Post/Article "Square and Cube Roots Quiz Set 009" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2019-08-18.

Posted by Parveen(Hoven),
Aptitude Trainer


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